Reuse of hemodialyzers is the standard practice in the field, having been first employed in the mid 1960's. Currently, in the United States, over 80% of all dialysis procedures are preformed with reused artificial kidneys. Standards for this practice were established by the Association for the Advancement of Medical Instrumentation (AAMI) in the mid 1980's and were later embraced by the Food and Drug Administration who subsequently published their own guidance document regarding dialyzer reuse.
Dialyzer reuse has been necessitated by lack of funding. Federal funding has been decreased in inflation-adjusted dollars by more than 90% since it was enacted in 1972. There are also documented clinical benefits to dialyzer reuse related to the prevention of humoral reactions to the materials of construction of the devices. Some of these reactions, such as acute anaphylaxis, can be lethal.
Reuse of the associated blood tubing sets is also known but much less frequently practiced because of the problems inherent with current reuse practices. When reuse of blood tubing is attempted in a clinical setting, it is only the arterial half of the pair that is reused since clot filtering screens are almost universally present in the bubble traps of the venous line which are very difficult to clean after exposure to blood. The ubiquity of these screens is notwithstanding the complete absence of evidence supporting their utility and the presence of data indicting these components as the source of clot formation on the downstream side of their surface thereby creating the exact problem they are implemented to prevent. Consequently, there are now commercially available venous blood tubing lines which contain no filter screen in the bubble trap and yet others which contain no bubble trap or clot filtering screen.
Reuse may be accomplished either manually, using apparatus designed and built by the dialysis provider, or by automated instruments which are commercially available. Although techniques vary somewhat, through the efforts of AAMI and HCFA (Health Care Finance Administration, now CMS), considerable standardization has occurred. Several quality assurance steps must be taken in order to qualify for federal reimbursement. These include assuring that: the proper concentration of disinfectant is used and that its residence time and duration are adequate, the disinfectant is rinsed out to acceptably low levels prior to the next use, the dialyzer is only used on the same patient, the small molecule transport rate is within 10% of its original value, and the device does not leak.
The various disinfectants that are used include formaldehyde, peracetic acid/hydrogen peroxide, heat, hot citric acid, and glutaraldehydes. Also, bleach and hydrogen peroxide are sometimes employed as oxidizing agents to both cleanse the dialyzers of retained organic material and improve their esthetic appearance. This can be important since the reuse standards stipulate that patients can refuse to reuse a dialyzer for any reason, including its appearance.
The economic pressures on providers of dialysis therapy continue to worsen worldwide as funding continues to be reduced. This is amplified by the continued inflation in labor and operating costs. The result is a continual search on the part of providers to reduce their costs and improve their efficiency. Even with the use of automated equipment, there is still a relatively large labor component attached to each reuse and, as previously noted, in the vast majority of cases only the dialyzer is reused with the blood tubing sets, needles, and IV sets still being discarded with every treatment.
Additionally, prior to each dialysis procedure, a member of the clinic's staff must still spend time assembling new blood tubing sets to the dialyzer, priming the air out of this extracorporeal circuit, setting the correct fluid level in the bubble traps, adjusting the dialysis machine to rinse (dialyze) the disinfectant out of the circuit, and, finally, performing a manual test of the priming solution to assure that the residual disinfectant level is below acceptable limits. In addition, there is a cost to train new employees who are involved in the reuse process and, since there is a fairly high turnover rate for these types of employees, this cost is not insignificant.
It is therefore desirable to provide a method and associated devices which could reduce the labor and supplies costs of providing dialysis treatments in clinical settings.
U.S. Pat. Nos. 4,552,721 and 4,707,335 to Fentress et al. describes the simultaneous reprocessing of the blood treatment device and its associated and connected blood tubing and other fluid lines without any instrumentation. However, the lack of instrumentation results in the inability to perform the quality assurance tests for small molecule and water transport rates and membrane integrity. Also, the unavailability of high flows and pressures, as can be applied with an instrument, eliminates the opportunity to remove residual organic material by shear forces.
It is therefore desirable to provide a reuse system with instrumentation, in order to provide high flows and pressures.
U.S. Pat. No. 4,695,385 to Boag describes an apparatus which was designed to also allow the simultaneous reprocessing of the dialyzer and associated blood tubing sets while they remained connected to, the dialysis machine. However, this ties up the dialysis machine during the reprocessing procedure, rendering the system non-viable for use in a dialysis clinic where it is necessary to treat multiple patients on the same machine in a day. This system has, therefore, been relegated to home use exclusively.
Similarly, U.S. Pat. No. 6,132,616 to Twardowski et al. describes a system where the dialyzer and connected blood tubing sets (the extracorporeal circuit) remain on the dialysis machine (which doubles as an automated reuse instrument) between treatments as it disinfects not only the extracorporeal circuit, but the dialysate and water purification fluid pathways simultaneously with hot water. Once again, this restricts the use of this system primarily to extra-clinical settings where only one patient will be using the dialysis instrument.
It is therefore desirable to provide a system that reprocesses the dialyzer and associated blood tubing away form the dialysis machine.
In-center hemodialysis is generally performed three times per week for between three and five hours.
This means that each hemodialysis machine can treat approximately two cycles of 3-4 patients for a total of 6-8 patients per week. However, it is becoming apparent that daily hemodialysis is the gold standard of care. In this method, hemodialysis is typically performed six days a week for between two to three hours. Daily hemodialysis more closely resembles normal kidney function than treatment three times a week. This means that patients have fewer negative side effects, and may also reduce some of the dietary restrictions and medications for patients.
As discussed above, most artificial kidneys are cleaned, sanitized, and reused. However, the blood tubing is generally not reused. Currently, Medicare as well as commercial insurer payments are based on the three treatments per week. Therefore, daily hemodialysis is not feasible in-center because of the added cost of the incremental blood tubing circuits and the associated time and labor required to set-up and tear-down the extracorporeal circuit between patient shifts. The current reimbursement system, along with the inability to effectively and time-efficiently reuse the venous and arterial blood lines are the main barriers to patients receiving the gold standard of care in clinics. Therefore it is desirable to provide a system that cleans and sanitizes blood tubing for reuse and to do so expediently so that two patient shifts could potentially be performed within approximately the same timeframe as a single shift is currently accomplished including the set-up and tear-down time.